CherryPy kicks some serious arse in the 'I am just a HTTP framework' category! As of version 3.2 it supports 4 types of storage for sessions by default:

• Ram
• File
• PostgreSQL
• Memcached

Redis is growing in popularity as an alternative to Memcached (and is fully supported on dotCloud!)

If you are not using pip yet. Install it and while you are at it consider using virtualenv too.

$ pip install cherrys

redis-py and CherryPy are required dependencies hence will be installed if necessary.

We recommend installing hiredis-py (a faster parser) as well.

$ pip install hiredis

To tell CherryPy which backend to use, we need to specify the storage_type for the sessions tool. You may want to read more about CherryPy configuration.

tools.sessions.storage_type : 'redis'

But CherryPy doesn't know Redis. Hence the first thing we need to do is add the cherrys RedisSession class to cherrypy.lib.sessions.

import cherrys
cherrypy.lib.sessions.RedisSession = cherrys.RedisSession

It is that simple!

There are 4 optional parameters you can set:

• host [127.0.0.1]
• port [6379]
• db [0]
• password [None]

A full config dictionary to activate Redis backed sessions would look like this.

config = {
    'tools.sessions.on' : True,
    'tools.sessions.storage_type' : 'redis',
    'tools.sessions.host' : 'REDIS_HOST',
    'tools.sessions.port' : REDIS_PORT,
    'tools.sessions.db' : REDIS_DB,
    'tools.sessions.password' : 'REDIS_PASSWORD'
    }